point acquisition THE CONSERVANC YACQUIRES AN ANCIENT ROCKSHELTER

The Conservancy Acquires an Ancient Rockshelter

The shelter’s Holocene deposits contain evidence of Great Basin climate after the last Ice Age.

acquisition

Researchers have long debated the post-glacial climate changes in North America and their concomitant effects on prehistoric peoples’ way of life. Was this a period of warmer and drier climate? If so, was it sufficiently warm and dry to account for changes in human subsistence and settlement patterns?

Leonard Rockshelter, the Conservancy’s latest Nevada preserve, contains evidence that can answer some of these questions for the western Great Basin area. The Conservancy used POINT funds to purchase a 640-acre parcel of land that includes the rockshelter from Newmont Gold Mining.

Dating from as early as 6,700 B.C. and possibly earlier, Leonard Rockshelter in the Humboldt Valley of western Nevada contains a long record of sporadic occupation that continues until at least A.D. 1400; indeed, the site is one of the oldest and one with the longest record in the western Great Basin.

The rockshelter was first discovered in 1936 when, during the course of bat guano mining operations, several ancient artifacts including an atlatl dart and shafts, wooden artifacts, and shell beads were discovered. Archaeologist Robert Heizer of the University of California excavated deposits in the shelter in 1949 and 1950, recovering basketry fragments, cordage nets, matting, an infant burial, and an atlatl dart which was radiocarbon dated to about 5000 B.C.Based on the presence of artifacts buried deeper in earlier guano deposits, Heizer postulated that human use of the site may have begun as early as roughly 11,000 years ago. Abstract images that were pecked into the tufa have been recorded at the back of the shelter which, based on their position relative to the deposits and their style, suggest that they were made sometime between 1000 B.C. and A.D. 1000.

“Like Lovelock Cave and other caves in this area, Leonard Rockshelter was probably used as a temporary shelter and storage area, particularly for perishable items,” speculated Peggy McGuckian, a Bureau of Land Management (BLM) archaeologist in Nevada. “With the rock art present, the shelter may well have served some spiritual function as well.”

University of California researchers recovered pollen samples from the shelter in 1975 in the hopes that they could resolve the debate regarding post-glacial climate

Leonard Rockshelter was discovered in 1936. Artifacts found at the site indicate that humans may have used it as early as 11,000 years ago.

change. Geologist Ernst Antevs’s postulation that in the Great Basin this period was characterized by a warmer, drier climate known as “Antevs’s Altithermal” had long been questioned by other researchers. Analysis of the Leonard Rockshelter pollen record subsequently confirmed Antevs climatic reconstruction, while still leaving the question of the magnitude of climate change open.

“In areas such as the Great Basin, even small changes can have far-reaching consequences,” said University of California geologist Roger Byrne. “These changes caused the drying up of nearly all post-glacial lakes, which would have drastically affected the prehistoric peoples that were heavily dependent on them.” —Tamara Stewart